Convert CONFIG_SYS_PBSIZE to Kconfig

This converts the following to Kconfig:
   CONFIG_SYS_PBSIZE

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/configs/paz00_defconfig b/configs/paz00_defconfig
index b0e650e..df43008 100644
--- a/configs/paz00_defconfig
+++ b/configs/paz00_defconfig
@@ -14,6 +14,7 @@
 CONFIG_SYS_STDIO_DEREGISTER=y
 CONFIG_SYS_PROMPT="Tegra20 (Paz00) MOD # "
 CONFIG_SYS_MAXARGS=64
+CONFIG_SYS_PBSIZE=2087
 # CONFIG_CMD_IMI is not set
 CONFIG_CMD_GPIO=y
 CONFIG_CMD_MMC=y